The influences of coating alumina on the RF characteristics of packaged surface acoustic wave devices

This paper presents studies on the influences of alumina film overly coated on the chip surface on the RF characteristics of surface acoustic wave (SAW) devices during packaging process. An SAW resonator is taken as an example and the surface layer deformation of the chip substrate with different thicknesses of alumina overlay is simulated based on finite element method (FEM). The RF characteristics of the packaged devices in different cases are compared. The results show the overlay of appropriate thickness can improve the package effect on SAW devices.